Modern home laundry cleaning compositions are very reliable and efficient in removing soil from household clothing articles, linens, and the like. Household laundry detergent compositions are formulated to remove soil and stains from various kinds of dirt depositions in the fabric. Generally such formulations effectively remove dirt induced soil and are even effective in removing low level stains or soil from oil or grease sources. However, common laundry detergents are deficient in handling soil resulting from protein sources, e.g., blood, grass; or soil where the proteins are combined with oils or greases from animal or vegetable origin; or soils of heavy grease, fats, or starch origin.
In order to effectively remove these difficult soils, various compositions are being marketed as "pre-washes" or "pre-spotters." Such compositions are applied directly to the difficult stains before the washing process. The "pre-wash" compositions are formulated primarily to remove oily or greasy stains. For this purpose, such compositions rely principally upon organic based solvents such as hydrocarbons, halogenated hydrocarbons etc. in combination with hydrocarbon compatible surfactants. Such compositions effectively dissolve and/or emulsify oily or greasy stains. These compositions, however, are not nearly as effective in removing stains caused by protein sources such as blood, and grass; or from combined protein and fat sources such as sebum; or from fats and starches. These sources produce stains which are difficult to remove with solvent/surfactant combinations alone.
In an effort to treat protein, fat and starch based stains, some producers have resorted to the use of enzyme compositions that are available from various sources. These compositions employ protease, amylase, or lipase enzymes to attack protein, fat and starch based stains and chemically degrade these compounds so that they can more readily be removed by subsequent or concurrent treatment with conventional surfactants. While enzyme containing compositions are quite proficient in treating such stains, the enzymes themselves are quite susceptible to deactivation if mixed with other components, especially hydrocarbon solvents.
Thus the "pre-wash" manufacturer faces a dilemma if it is desired to effectively treat both oil and grease based stains as well as protein, fat and/or starch based stains on the same garments. Since enzymes are incompatible with hydrocarbon solvents, it has heretofore been impractical to devise a single enzyme-hydrocarbon solvent product that will effectively treat both grease stains and protein, fat and/or starch stains. It is not practical to provide two separate formulations, one enzyme and one solvent, since separate compositions would be more costly; and cause twice the work for the user. Therefore such separate treatment procedures are unacceptable to the consumer.
The ideal solution to the problem would be a "pre-wash" composition which would simply and easily treat both grease and protein, fat, and/or starch stains in a single treatment. Such a composition should have a reasonable storage life during which the enzymes would not excessively degrade or deteriorate; it should be quite liquid so that it could be easily applied to the stains, as by spraying; it should be a single phase composition, so that one component would not settle out thereby requiring agitation or shaking to mix the components before use; and it should be dispersible in, or miscible with laundry wash water so that it is easily removed when the fabrics are subsequently washed in a conventional washing machine.
The present invention solves the problems enumerated above.